In the field of industrial automation, programmable logic controllers and field extension modules control large numbers of electronic actuators. Due to the wide range of actuators and their different performance requirements a vast variety of signal drives exist, providing actuator signals with different ranges of drive voltage or current. In between these ranges many proprietary signal interfaces exist requiring the customization of the electronic drive to match the required actuator input.
In order to avoid separate board designs for each type of actuator, it is desired to have an integrated solution that provides accurate voltage controlled current and voltage supply with scalable output levels.
A conventional control loop needs a shunt resistor in order to measure the voltage drop across this shunt resistor and feed the result back into the negative input terminal of an amplifier, e.g., via an instrumentation amplifier and a resistor, thereby closing the current control loop.